“Solid state fermentation for the production of alkaline protease by Bacillus cereus 1173900 using proteinaceous tannery solid waste.
ABSTRACT Animal fleshing, the major proteinaceous solid waste
generated from leather industry, was used as substrate
for the production of alkaline protease by Bacillus
cereus 1173900 in solid-state fermentation (SSF).
Maximum protease activity of 12,310 U/g was observed
at 60 h in SSF crude extract. The extracted
protease enzyme was purified by 53.64-fold through
ammonium sulphate precipitation and chromatography
separation in Sephadex G-100. The purified protease
had a specific activity of 201.6 (U/mg). The molecular
weight of the purified enzyme was 66 kDa, determined
by SDS–PAGE. The zymogram also revealed a clear
hydrolytic zone due to proteolytic activity, which
coincided with the band obtained with SDS–PAGE.
Enzyme activity was inhibited by EDTA, suggesting
that the enzyme belongs to metalloprotease(s).
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ABSTRACT: Cow dung, a cheap and easily available source of energy, was used as the substrate for the production of alkaline protease by solid-state fermentation using the Bacillus subtilis strain VV. In order to achieve the maximum yield of this enzyme, the following optimum process parameters are needed: fermentation period (72 h), pH (10.0), moisture content (140%), inoculum (25%), temperature (30-40°C), carbon source (2% (w/w) maltose) and nitrogen source (1% (w/w) urea). The protease was stable over a broad temperature range (30-50°C) and pH (8.0-10.0), with maximum activity at 50°C and pH 10.0. Among the divalent ions tested, Ca(2+) (0.01 M) increased enzyme activity. The purified protease, after being subjected to sodium dodecyl sulphate-polyacrylamide gel electrophoresis, was found to have a molecular mass of 38.5 kDa. The enzyme was solvent-and surfactant-stable and showed activity even after 24 h incubation along with various commercially available detergents. This enzyme possessed dehairing properties for animal hide after 16 h of incubation at room temperature. From these results it is evident that cow dung is a potential substrate for the production of a detergent-stable, dehairing protease by B. subtilis. This enzyme has a lot of potential applications in the detergent and leather-processing industries.SpringerPlus 01/2012; 1:76.